Effect of substrate temperature on the microstructural and optical properties of chemical molecular beam deposited sb2s3 films

In this work, Sb_xS_y thin films were grown on glass substrates for the first time using the chemical molecular beam deposition method in the atmospheric pressure hydrogen flow. The structural, morphological and optical properties of Sb_xS_y thin films grown at different substrate temperatures of 300 °C, 350 °C, 400 °C and 450 °C were studied. XRD results showed that the Sb_xS_y thin films grown at different substrate temperatures have an orthorhombic crystal structure. Phase analysis indicated a weakening of Sb-S bonds with increasing substrate temperature. Also, the grain sizes of all obtained thin films ranged from 0.5 to 3 µm. The increase in temperature caused the grains to grow and the spaces between them to increase. Optical experiments reveal that as the substrate temperature increases, the optical band gap energy of the films increases from 1.52 eV to 1.73 eV, as well as an increase in the Urbach energy from 0.11 eV to 0.44 eV. The experimental values of the band gap for Sb₂S₃ films are near the optimum value for photovoltaic conversion.